Friday, July 6, 2007
Organic food really is better for you than conventionally grown crops, according to new research.
A 10-year study comparing organic tomatoes with rival produce suggests they have almost double the amount of heart-protective antioxidants called flavonoids.
According to the new findings levels of the chemicals quercetin and kaempferol were found to be on average 79 and 97 per cent higher, respectively, in organic tomatoes.
Flavonoids such as these can fight heart disease, blood pressure and strokes and have also been linked to staving off some forms of cancer and dementia, says food chemist Alyson Mitchell who led the research.
Differences in soil quality, irrigation practices and the handling of harvested produce have made direct comparisons difficult in the past, says Dr Mitchell.
So in this study, due to be published in the Journal of Agricultural and Food Chemistry, the researchers used data from a long-term project in which standardised farming techniques are used to reveal trends in crop productivity.
Dr Mitchell, of California University, said the findings can be explained by the availability of nitrogen. Flavonoids are produced as a defence mechanism that can be triggered by nutrient deficiency.
The inorganic nitrogen in conventional fertiliser is easily available to plants and so, the team suggests, the lower levels of flavonoids are probably caused by over-fertilisation.
Previous research has found no differences between organic and conventional crops such as wheat or carrots.
Meanwhile, a study proclaiming organic milk had higher levels of omega-3 fatty acids failed to convince the UK's Food Standards Agency (FSA), which pointed out that these short-chained fatty acids do not have the health-promoting benefits offered by long-chained omega-3 oils.
This latest study does not prove that a healthy diet must be organic, reports New Scientist.
The evidence of health benefits for flavonoids is conflicting, says Dr Peter Bramley at Royal Holloway, University
And even if such benefits exist, higher flavonoid levels do not necessarily make organic food healthier, says Sir John Krebs, former chair of the FSA and now at the University of Oxford.
He said: "This depends on the relevance of the differences to the human body. Tomato ketchup has higher levels of lycopene (a strong antioxidant) than either organic or conventional tomatoes. So if you wanted lots of lycopene you should eat ketchup."
Flavonoids are also found in chocolate as well as fruit and vegetables and red wine and tea. Doctors say eating five portions of fruit and vegetables a day is the best way of getting the heart-protective antioxidants.
Studies have suggested flavonoids can reduce the body's so-called bad cholesterol that causes the hardening of the arteries.
(courtsey of Life,Style,Extra UK) http://www.lse.co.uk